This invention relates to compositions, preferably in the form of clear, single phase liquids, that are particularly useful in removing aerosolized, polymerized, or airborne hardened grease from kitchen surfaces.
Airborne grease, polymerized grease, or aerosolized grease are names applied to the type of greasy soil which results from the deposition of oil particles on kitchen surfaces during various cooking processes involving edible fats and oils, i.e., deep frying, grill frying, etc. During such frying of foods, particles of fats and oils spatter and splash and eventually deposit on various kitchen surfaces such as countertops, floors, walls and appliance surfaces. This type of greasy soil or "aerosolized grease," upon contact with the substrate undergoes a number of chemical reactions and forms a semi-solid gel structure, which strongly adheres to the substrate. The result is a difficult to remove greasy soil that contains a significant amount of insoluble and polar fractions.
The following are the major changes that have been found to occur in the physical and chemical properties of cooking oils as the oils are treated under deep frying conditions and aged on kitchen surfaces:
Initially the oil is a liquid (at room temperature), and it is composed of a mixture of low molecular weight unsaturated triglycerides with no significant polar compounds (free fatty acids). This oil has a viscosity of about 60 cps and adheres weakly to the substrate.
As the oil is exposed to high temperature, air, and moisture during deep frying (and following aging at room temperature), various chemical reactions, including polymerization, hydrolysis, and oxidation take place. The rate and extent of these reactions depend on the nature of the oil, the temperature and the operating conditions. Key physical and chemical changes in oil properties which take place upon this treatment can be summarized as follows:
1. Substantial reduction in the level of unsaturated fractions and formation of dimers and trimers, as the oil undergoes thermal and oxidative polymerization. This results in a major increase in oil viscosity as the oil transforms from a liquid to a gel (or solid, in the case of linseed oil).
2. Significant increase in the free fatty acid content of the oil. This results in increased tackiness and greater adhesion to the substrate, particularly glass and metal surfaces via polar bonds.
Commercial multipurpose cleaners containing mixtures of surfactant and salt are not effective in removing such greasy soil. It has now been discovered, though, that it is possible to formulate a nonabrasive, liquid cleaning composition which effectively removes such greasy soil. The proposed composition utilizes high alkalinity to neutralize the polar groups of the soil to aid detachment, a solvent to penetrate and to swell the soil, and a surfactant to wet and disperse the soil.